Embodiments of the invention relate generally to diagnostic imaging and, more particularly, to a method and apparatus for dual energy CT spectral imaging that provides for accurate blood vessel stenosis visualization and quantification.
Typically, in computed tomography (CT) imaging systems, an x-ray source emits a fan-shaped beam toward a subject or object, such as a patient or a piece of luggage. Hereinafter, the terms “subject” and “object” shall include anything capable of being imaged. The beam, after being attenuated by the subject, impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array is typically dependent upon the attenuation of the x-ray beam by the subject. Each detector element of the detector array produces a separate electrical signal indicative of the attenuated beam received by each detector element. The electrical signals are transmitted to a data processing system for analysis which ultimately produces an image.
Certain imaging procedures that make use of CT imaging can be challenging based on the presence of imaging artifacts that appear in a reconstructed image (i.e., beam hardening artifacts). For example, accuracy of stenosis measurements in blood vessels is a challenge in CT imaging, especially in the presence of plaque in the vessels that includes high density calcium. The high density calcium plaque in blood vessels introduces a blooming effect that overestimates the true extent of the plaque in the vessel and significantly affects the visualization of the true contrast flow in the vessels. This distorting of the true extent of the plaque in the vessel leads to inaccurate stenosis measurements.
Therefore, it would be desirable to design an apparatus and method that provides for more accurate quantification and visualization of stenosis in blood vessels by reducing the blooming effects of high density plaque in reconstructed CT images.